The content of the invention
The technology of the present invention solves the problems, such as:Overcome the deficiencies in the prior art, proposes based on average life span to estimate and cover special
The Geostationary Satellite's of Caro emulation, realize the prediction to satellite mean mission duration time, MMDT (MMD).
The present invention technical solution be:Geostationary Satellite's based on MLE and Monte-Carlo Simulation, this method
Include the following steps:
(1), criterion is terminated according to the lifetime of satellite, determines each subsystem units product that the lifetime of satellite can be caused to terminate;
(2), each subsystem units product that the lifetime of satellite can be caused to terminate determined by step (1) is divided into random mistake
Imitate two class of product and wearout failure product;
(3), the life model of random failure product is established, according to each unit crash rate of satellite random failure product and Qi Ke
By property logical relation, using monte carlo simulation methodology, the mean time to failure of satellite system random failure is tried to achieve
MTTF, is derived from satellite system random failure reliability function RAt random(t);
(4), the life model of wearout failure product is established, is closed according to each unit reliability logic of satellite wearout failure product
System and its wear-out life average and variance, using monte carlo simulation methodology, are calculated average and the side of satellite wear-out life
Difference estimation, is derived from satellite system wearout failure reliability function RConsume(t);
(5), satellite system random failure and wearout failure function are subjected to integration analysis, obtain the satellite task that is averaged and continue
Time MMD, in this, as the life prediction result of satellite system.
The life model of the random failure product is the reliability model of the product.
Step (3) are implemented as:
(3.1), simulation parameter is initialized, the simulation parameter includes:Simulation times thresholding N, default emulation step number threshold value
K, analysis time t, analysis time step delta t, emulation step number i;
(3.2), emulation step number i is added 1, renewal emulation step number i;
(3.3), initialize simulation times n and meet that the reliability number r of reliability requirement is 0;
(3.4), simulation times n is added 1;
(3.5), random number is produced as random Reliability index by the use of the random function of MATLAB, produced according to random failure
The life model of product, calculates the failure reliability index corresponding out-of-service time of each random failure product unit, with reference to
Reliability logic relation between machine failure each unit of product, obtains the service life T of random failure products, enter step (3.6);
(3.6), the service life T of random failure product is comparedsThe index of aging T given with satellitemSize, if random lose
Imitate the service life T of productsThe index of aging T given more than or equal to satellitem, represent that random Reliability index at this time meets the system longevity
Index request is ordered, the reliability number r for meeting reliability requirement is added 1, reliability number r is updated, otherwise, as simulation times n
During not up to simulation times thresholding N, repeat step (3.4)~step (3.6), otherwise, enters step (37);
(3.7), analysis time t corresponding satellite system reliability is calculatedAnalysis time t is according to simulation step length Δ
T is incremented by, will analysis time t plus Δ t with replacement analysis time t;
(3.8), emulation step number is added 1, renewal emulation step number i, compares emulation step number and be less than or equal to default emulation step number
Threshold k, then repeat step (3.2)~step (3.8), obtains the longevity of the random failure product corresponding to each simulation analysis time
Order Ts, otherwise, enter step (3.9);
(3.9), each simulation analysis time t+k Δ t, the service life T of corresponding random failure products, make satellite system
System reliability curve, is fitted curve to obtain satellite system random failure function RAt random(t)。
Judged in step (3.5) by the reliability logic relation between each unit of random failure product, obtain with
The service life T of machine failure productsSpecific method be:
When the reliability logic relation between each unit of random failure product is parallel relationship, put down before choosing first-time fault
The greater of equal time MTTF, the service life T as random failure products;
When the reliability logic relation between each unit of random failure product is series relationship, put down before choosing first-time fault
The smaller of equal time MTTF, the service life T as random failure products;
When the reliability logic relation between each unit of random failure product is voting relation, put down before choosing first-time fault
The summation of equal time MTTF, the service life T as random failure products。
The life model of the wearout failure product uses normal distribution form, is specially:
Wherein:
μLoss- satellite wear-out life average;
σLoss- satellite wear-out life variance.
Step (4) are implemented as:
(4.1), wearout failure product simulation parameter is initialized, the wearout failure product simulation parameter includes simulation times
Thresholding N2;
(4.2), the lifetime data of collection consume class unit, calculates first moment, second moment obtains wearout failure attrition
Service life average and variance, for there are the wearout failure product of redundancy backup, its wear-out life is calculated using Monte-Carlo Simulation
Average and variance;
(4.3), according to wearout failure attrition service life average and variance, the life model of wearout failure product is established,
Carry out N2Secondary Monte-Carlo Simulation calculates, and obtains the wearout failure time simulation value of each random failure product;
(4.4), according to the wearout failure time simulation result of wearout failure product, satellite average loss service life average is obtained
μLossAnd variances sigmaLossEstimation so that obtain satellite wearout failure average life span estimation, also therefore obtain wearout failure
Reliability function RConsume(t)。
The calculation formula of step (5) the satellite mean mission duration time, MMDT MMD is:
In formula, T is truncated time.
The truncated time T chooses 1.5 times of satellite design lifetime requirement.
Compared with the prior art, the invention has the advantages that:
(1), satellite failure is divided into random failure and wearout failure by the present invention, by monte carlo simulation methodology, is realized
Life prediction to satellite mean mission duration time, MMDT.After satellier injection, status information, the failure of satellite are obtained by remote measurement
Information, can carry out life prediction according to the new state of satellite near real-time, compared to existing with satellite time or satellite in orbit
The result more science that projected life is predicted as the lifetime of satellite, it is also more objective to calculate.
(2), the present invention has fully ensured that the convergence of process, so as to also ensure that Forecasting Methodology by simulation means
Precision.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.
As shown in Figure 1, the Geostationary Satellite's provided by the invention based on MLE and Monte-Carlo Simulation, including such as
Lower step:
(1), criterion is terminated according to the lifetime of satellite, determines each subsystem units product that the lifetime of satellite can be caused to terminate;
The satellite operation on orbit service life refers generally to satellite since being entered the orbit transmitting, until operation on orbit is expendable because occurring
The duration that wearout failure causes satellite major function to be lost occurs for failure or end of lifetime.Judge whether the lifetime of satellite terminates
First it should be understood that functional performance of the satellite system during actual task, undergoing mission profile and environmental condition generally comprises
It is satellite orbital altitude, space environment, image quality requirement, orbit maneuver requirement, the orbit maneuver time, target location accuracy, flat
Platform gesture stability Capability Requirement, data transfer and storage capacity requirement, operation on orbit life requirements etc., tasks clear is successfully determined
Justice.Then, reselection judges the parameter whether lifetime of satellite terminates, these parameters should be understood that, quantify, and can reflect satellite comprehensively
Function, performance state, generally lose from load, orbit maneuver, gesture stability, power supply and distribution, data transfer and storage etc. refinement
Imitate criterion.
(2), each subsystem units product that the lifetime of satellite can be caused to terminate determined by step (1) is divided into random mistake
Imitate two class of product and wearout failure product;
The classification that GPS and NASA fails satellite is used for reference, satellite failure is divided into random failure and wearout failure by this step
Two major classes.Random failure refers mainly to the burst failure of electronic product in satellite;Wearout failure relates generally to satellite clock, the energy, electricity
Source power, lubrication, mechanism number of revolutions etc. show as gradually weakening the failure of characteristic within the lifetime of satellite phase.Will be in lifetime
The product for showing as random failure is divided into random failure product, and the product that wearout failure is shown as in lifetime is divided into
Wearout failure product.To not only there are random failure but also there are the unit of wearout failure, only considering random failure at this time, being classified as
Random failure product.
(3), the life model of random failure product is established, according to each unit crash rate of satellite random failure product and Qi Ke
By property logical relation, using monte carlo simulation methodology, the mean time to failure of satellite system random failure is tried to achieve
MTTF, is derived from satellite system random failure reliability function RAt random(t);
The life model of the random failure product can select the reliability model of the product, random failure product can
Exponential distribution form can be used by property function R.I.e.:
R=e-λt
Wherein, R is reliability, and λ is crash rate, and t is the defined time;
Satellite electron class unit random failure distribution pattern can also use Weibull distribution to represent.
Satellite random failure can be characterized using MTTF indexs, specifically try to achieve satellite system using monte carlo simulation methodology
The mean time to failure MTTF processes of random failure are as shown in Figure 2:
(3.1), simulation parameter is initialized, the simulation parameter includes:Simulation times thresholding N, default emulation step number threshold value
K, analysis time t, analysis time step delta t, emulation step number i.In view of calculating the reason such as time and convergence rate, simulation times
Thresholding N generally may be set to 10000 times, and analysis time t is arranged to that satellite is in-orbit to require working time, analysis time step delta t
It is configured as needed, generally 1 day, January etc., emulation step number i is initialized as 0, when presetting emulation step number threshold k by analyzing
Between total duration determine.
(3.2), emulation step number i is added 1, renewal emulation step number i;
(3.3), it is 0 to initialize the simulation times n and Reliablility simulation number r met the requirements;
(3.4), simulation times n is added 1;
(3.5), random number is produced as random Reliability index by the use of the random function of MATLAB, produced according to random failure
The life model of product, calculates the failure reliability index corresponding out-of-service time of each random failure product unit, with reference to
Reliability logic relation between machine failure each unit of product, obtains the service life T of random failure products, enter step (3.6);
Judged by the reliability logic relation between each unit of random failure product, obtain random failure product
Service life TsSpecific method be:
When the reliability logic relation between each unit of random failure product is parallel relationship, put down before choosing first-time fault
The greater of equal time MTTF, the service life T as random failure products;
When the reliability logic relation between each unit of random failure product is series relationship, put down before choosing first-time fault
The smaller of equal time MTTF, the service life T as random failure products;
When the reliability logic relation between each unit of random failure product is voting relation, put down before choosing first-time fault
The summation of equal time MTTF, the service life T as random failure products。
Product for taking redundant configuration strategy on satellite, in Reliablility simulation with logic criterion go description product it
Between redundancy relationship.If unit A and unit B is parallel redundancy, the criterion of MTTF is in emulation:MTTF's is larger in selection A or B
Person;If unit A and unit B is series relationship, the criterion of MTTF is in emulation:Select the smaller of MTTF in A or B.For table
Certainly relation, the criterion of MTTF is in emulation:Select the sum of A and BMTTF.
(3.6), the service life T of random failure product is comparedsThe index of aging T given with satellitemSize, if random lose
Imitate the service life T of productsThe index of aging T given more than or equal to satellitem, represent that random Reliability index at this time meets the system longevity
Index request is ordered, the reliability number r for meeting reliability requirement is added 1, reliability number r is updated, otherwise, as simulation times n
During not up to simulation times thresholding N, repeat step (3.4)~step (3.6), otherwise, enters step (3.7);
(3.7), analysis time t corresponding satellite system reliability is calculatedAnalysis time t is according to simulation step length Δ
T is incremented by, will analysis time t plus Δ t with replacement analysis time t;
(3.8), emulation step number is added 1, renewal emulation step number i, compares emulation step number and be less than or equal to default emulation step number
Threshold k, then repeat step (3.2)~step (3.8), obtains the longevity of the random failure product corresponding to each simulation analysis time
Order Ts, otherwise, enter step (3.9);
(3.9), each simulation analysis time t+k Δ t, the service life T of corresponding random failure products, make satellite system
System reliability curve, is fitted curve to obtain satellite system random failure function RAt random(t)。
Satellite system random failure function RAt random(t) form is:
Simulation data result includes satellite system stochastic life MTTF, when carrying out lifetime of satellite prediction calculating, can also incite somebody to action
It asks inverse to be converted into satellite crash rate level.
(4), the life model of wearout failure product is established, is closed according to each unit reliability logic of satellite wearout failure product
System and its wear-out life average and variance, using monte carlo simulation methodology, are calculated average and the side of satellite wear-out life
Difference estimation, is derived from satellite system wearout failure reliability function RConsume(t);Satellite wearout failure product refers generally on satellite
Limited life item, usually there are specific wearout failure mechanism, on-orbit fault is generally rendered as consuming, drifts about, fatigue and moves back
Change etc., such as the decay of solar battery array output power, the limitation of accumulator cell charging and discharging cycle-index, electromechanical movable part component lubrication not
Wear out failure caused by foot etc..
The life model of wearout failure product uses normal distribution form.Specially:
Wherein:
μLoss- satellite wear-out life average;
σLoss- satellite wear-out life variance.
Specifically simulation process is:
(4.1), wearout failure product simulation parameter is initialized, the wearout failure product simulation parameter includes consume unit
Choose number, simulation times thresholding N2;Simulation times thresholding N2It generally may be set to 10000 times, can be set again according to convergence rate
It is fixed.
(4.2), the lifetime data of collection consume class unit, calculates first moment, second moment obtains wearout failure attrition
Service life average and variance, for there are the wearout failure product of redundancy backup, its wear-out life is calculated using Monte-Carlo Simulation
Average and variance;
It is different that the parameter in its service life is characterized due to different product, such as storage battery circulation cycle, mechanical movable part rotation time
Number etc. is, it is necessary to be converted into unified chronomere, easy to carry out life prediction, also needs to consider satellite consume class unit redundant configuration
Situation, such as flywheel, Gyro, storage battery group redundancy scheme.
If the unit also wants computing redundancy unit wear-out life mean μ and variances sigma there are redundancy backup;Redundancy is set
The unit of meter, wear-out life mean μ and variances sigma after backup are calculated according to type of backup and logical relation.For existing
The random failure product of redundancy backup, its wear-out life average and variance are calculated using Monte-Carlo Simulation.
(4.3), according to wearout failure attrition service life average and variance, the life model of wearout failure product is established,
Carry out N2Secondary Monte-Carlo Simulation calculates, and obtains the wearout failure time simulation value of each random failure product;
(4.4), according to the wearout failure time simulation result of wearout failure product, satellite average loss service life average is obtained
μLossAnd variances sigmaLossEstimation so that obtain satellite wearout failure average life span estimation, also therefore obtain wearout failure
Reliability function RConsume(t)。
The reliability function R of satellite wearout failureConsume(t) form is:
(5), satellite system random failure and wearout failure function are subjected to integration analysis, obtain the satellite task that is averaged and continue
Time MMD, in this, as the life prediction result of satellite system.
As shown in figure 4, the theoretical calculation formula of satellite mean mission duration time, MMDT MMD is:
R (t) --- mission reliability pattern function;
T --- truncated time.
The satellite mean mission duration time, MMDT MMD service lifes of the whole star of satellite of the present invention depend on the reliability curve of system, and
Satellite system reliability curve is by satellite random failure and the coefficient result of wearout failure.
Satellite mean mission duration time, MMDT MMD is:
1.5 times are required since service life extrapolation is limited solely to projected life, when asking for satellite average life span estimation, is cut
The tail time chooses 1.5 times of projected life requirement.
It is not described in detail in this specification and partly belongs to general knowledge well known to those skilled in the art.